Bacterial flora of the appendix fossa in appendicitis and postoperative wound infection

Characteristics of appendicitis after immune checkpoint inhibitor therapy among cancer patients

PURPOSE

Immune checkpoint inhibitor (ICI) therapy has revolutionized cancer care but is associated with immune-related adverse events (irAEs). Recent case reports raised the concern that acute appendicitis may be an irAE. In this study, we sought to describe the disease course of post-ICI therapy appendicitis and its associated complications.

METHODS

Adult patients who had an International Classification of Diseases code for appendicitis within the first 2 years after initiating ICI therapy from January 2010 to April 2021 and who had imaging evidence of appendicitis were studied retrospectively.

RESULTS

13,991 patients were identified who had ICI exposure during the study period, 44 had codes for appendicitis, 10 of whom met the inclusion criteria. Their median age at the time of diagnosis was 59 years. The median time from ICI therapy initiation to appendicitis onset was 188 days. The most common presenting symptoms were abdominal pain (70%) and fever (40%). Abscesses were present in two patients, and a perforation was present in one. All 10 patients received broad-spectrum antibiotics. Five patients needed surgery or interventional radiology drainage. Nine patients had resolution of appendicitis symptoms after treatment.

CONCLUSION

Post-ICI therapy appendicitis is rare but presents similarly to and has similar complications rates as conventional appendicitis. Appendectomy remains the mainstay of treatment, but its use can be limited in cancer patients. The decision to continue ICI therapy remains at the discretion of the clinician. Further studies are needed to bring awareness to and advance the understanding of this clinical entity.

Microbial Epidemiology of Acute and Perforated Appendicitis: A Post-Hoc Analysis of an EAST Multicenter Study

BACKGROUND

There are significant practice variations in antibiotic treatment for appendicitis, ranging from short-course narrow spectrum to long-course broad-spectrum. We sought to describe the modern microbial epidemiology of acute and perforated appendicitis in adults to help inform appropriate empiric coverage and support antibiotic stewardship initiatives.

METHODS

This is a post-hoc secondary analysis of the Multicenter Study of the Treatment of Appendicitis in America: Acute, Perforated, and Gangrenous (MUSTANG) which prospectively enrolled adult patients (age ≥ 18 years) diagnosed with appendicitis between January 2017 and June 2018 across 28 centers in the United States. We included all subjects with positive microbiologic cultures during primary or secondary (rescue after medical failure) appendectomy or percutaneous drainage. Culture yield was compared between low- and high-grade appendicitis as per the AAST classification.

RESULTS

A total of 3,471 patients were included: 230 (7%) had cultures performed, and 179/230 (78%) had positive results. Cultures were less likely to be positive in grade 1 compared to grades 3, 4, or 5 appendicitis with 2/18 (11%) vs 61/70 (87%) (p < .001). Only 1 subject had grade 2 appendicitis and culture results were negative. E. coli was the most common pathogen and cultured in 29 (46%) of primary appendectomy samples, 16 (50%) of secondary, and 44 (52%) of percutaneous drainage samples.

CONCLUSION

Culturing low-grade appendicitis is low yield. E. coli is the most commonly cultured microbe in acute and perforated appendicitis. This data helps inform empiric coverage for both antibiotics alone and as an adjunct to operative or percutaneous intervention.

Septic shock caused by acute appendicitis complicated with abscess formation within mesoappendix: A case report

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Appendicitis can cause septic shock.

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Abscess within mesoappendix led to septic shock.

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Appendectomy is an effective rescue therapy for acute appendicitis complicated with septic shock.

Introduction

Acute appendicitis is the most common surgical emergency and may present with a wide variety of clinical manifestations. In rare circumstances, appendicitis can cause life-threatening complications e.g. septic shock. We present a case of septic shock caused by acute appendicitis complicated with abscess formation within the mesoappendix.

Presentation of case

A 42-year-old male was presented with migratory right lower abdominal pain, accompanied by septic shock and acute kidney failure. We performed emergency appendectomy and unexpectedly observed an abscess within the mesoappendix during surgery. The patient received antibiotic therapy perioperatively. Escherichia coli and Klebsiella pneumoniae subspecies were isolated from the intraoperative pus specimen, and Bifidobacterium was isolated from his preoperative blood culture. Histopathology revealed acute suppurative appendicitis. The patient recovered uneventful and was discharged 5 days after surgery.

Discussion

We believe that the septic shock was associated with the small abscess formation in the mesoappendix. Bacteria within the mesoappendix could enter the bloodstream through the mesoappendiceal vessel and then septic shock and kidney failure occurred sequentially. We assume that the abscess within the mesoappendix was caused by a tiny perforation from the mesoappendiceal side.

Conclusion

The case of acute appendicitis complicated with abscess formation within mesoappendix explains one of the causes which may lead to septic shock.

The Brain-Intestinal Mucosa-Appendix- Microbiome-Brain Loop

The brain and the gut are connected from early fetal life. The mother's exposure to microbial molecules is thought to exert in utero developmental effects on the fetus. These effects could importantly underpin the groundwork for subsequent pathophysiological mechanisms for achieving immunological tolerance and metabolic equilibrium post birth, events that continue through to 3-4 years of age. Furthermore, it is understood that the microbiome promotes cues that instruct the neonate's mucosal tissues and skin in the language of molecular and cellular biology. Post birth mucosal lymphoid tissue formation and maturation (most probably including the vermiform appendix) is microbiota-encouraged co-establishing the intestinal microbiome with a developing immune system. Intestinal mucosal tissue maturation loops the brain-gut-brain and is postulated to influence mood dispositions via shifts in the intestinal microbiome phyla. A plausible appreciation is that dysregulated pro-inflammatory signals from intestinal resident macrophages could breach the loop by providing adverse mood signals via vagus nerve afferents to the brain. In this commentary, we further suggest that the intestinal resident macrophages act as an upstream traffic controller of translocated microbes and metabolites in order to maintain local neuro-endocrine-immunological equilibrium. When macrophages are overwhelmed through intestinal microbiome and intestinal epithelial cell dysbiosis, pro-inflammatory signals are sustained, which may then lead to mood disorders. The administration of probiotics as an adjunctive medicine co-administered with antidepressant medications in improving depressed mood may have biological and clinical standing.

The intra- and extraluminal appendiceal microbiome in pediatric patients: A comparative study

Intestinal microbiota is involved in metabolic processes and the pathophysiology of various gastrointestinal disorders. We aimed to characterize the microbiome of the appendix in acute pediatric appendicitis comparing extraluminal and intraluminal samples.Between January and June 2015, 29 children (3-17 years, mean age 10.7 ± 3.4 years, sex M:F = 2.6:1) undergoing laparoscopic appendectomy for acute appendicitis were prospectively included in the study. Samples for bacterial cultures (n = 29) and 16S ribosomal desoxyribonucleic acid (rDNA) sequencing (randomly chosen n = 16/29) were taken intracorporeally from the appendiceal surface before preparation ("extraluminal") and from the appendiceal lumen after removal ("intraluminal"). The degree of inflammation was histologically classified into catarrhal, phlegmonous, and gangrenous appendicitis.Seventeen bacterial species were cultivated in 28 of 29 intraluminal samples and 4 species were cultivated in 2 of 29 extraluminal samples. Using 16S rDNA sequencing, 267 species were detected in intraluminal but none in extraluminal samples. Abundance and diversity of detected species differed significantly between histological groups of acute appendicitis in bacterial cultures (P = .001), but not after 16S rDNA sequencing.The appendiceal microbiome showed a high diversity in acute pediatric appendicitis. The intraluminal microbial composition differed significantly depending on the degree of inflammation. As bacteria were rarely found extraluminally by culture and not at all by sequencing, the inflammation in acute appendicitis may start inside the appendix and spread transmurally.

Evaluation of the microbiome in children's appendicitis

BACKGROUND/AIM

The role of the microbiome has been widely discussed in the etiology of appendicitis. The primary aim was to evaluate the microbiome in the normal appendix and in appendicitis specifically divided into the three clinically and histopathologically defined grades of inflammation. Secondary aims were to examine whether there were any microbiome differences between proximal and distal appendices, and relate the microbiome with histopathological findings.

METHODS

A prospective pilot study was conducted of children undergoing appendectomy for appendicitis. The diagnosis was based on histopathological analysis. Children with incidental appendectomy were used as controls. The proximal and distal mucosa from the appendices were analyzed with 16S rRNA gene sequencing.

RESULTS

A total of 22 children, 3 controls and 19 appendicitis patients; 11 phlegmonous, 4 gangrenous, and 4 perforated appendices, were prospectively included. The amount of Fusobacterium increased and Bacteroides decreased in phlegmonous and perforated appendicitis compared to controls, but statistical significance was not reached, and this pattern was not seen in gangrenous appendicitis. No relation could be seen between different bacteria and the grade of inflammation, and there was a wide variation of abundances at phylum, genus, and species level within every specific group of patients. Further, no significant differences could be detected when comparing the microbiome in proximal and distal mucosa, which may be because the study was underpowered. A trend with more abundance of Fusobacteria in the distal mucosa was seen in appendicitis patients with obstruction (25 and 13 %, respectively, p = 0.06).

CONCLUSION

The pattern of microbiome differed not only between groups, but also within groups. However, no statistically significant differences could be found in the microbiome between groups or clinical conditions. No correlation between a specific bacteria and grade of inflammation was found. In the vast majority of cases of appendicitis, changes in microbiome do not seem to be the primary event. Since there seem to be differences in microbiome patterns depending on the sample site, the exact localization of biopsy sampling must be described in future studies.

Culture-independent evaluation of the appendix and rectum microbiomes in children with and without appendicitis

PURPOSE

The function of the appendix is largely unknown, but its microbiota likely contributes to function. Alterations in microbiota may contribute to appendicitis, but conventional culture studies have not yielded conclusive information. We conducted a pilot, culture-independent 16S rRNA-based microbiota study of paired appendix and rectal samples.

METHODS

We collected appendix and rectal swabs from 21 children undergoing appendectomy, six with normal appendices and fifteen with appendicitis (nine perforated). After DNA extraction, we amplified and sequenced 16S rRNA genes and analyzed sequences using CLoVR. We identified organisms differing in relative abundance using ANOVA (p<0.05) by location (appendix vs. rectum), disease (appendicitis vs. normal), and disease severity (perforated vs. non-perforated).

RESULTS

We identified 290 taxa in the study's samples. Three taxa were significantly increased in normal appendices vs. normal rectal samples: Fusibacter (p = 0.009), Selenomonas (p = 0.026), and Peptostreptococcus (p = 0.049). Five taxa were increased in abundance in normal vs. diseased appendices: Paenibacillaceae (p = 0.005), Acidobacteriaceae GP4 (p = 0.019), Pseudonocardinae (p = 0.019), Bergeyella (p = 0.019) and Rhizobium (p = 0.045). Twelve taxa were increased in the appendices of appendicitis patients vs. normal appendix: Peptostreptococcus (p = 0.0003), Bilophila (p = 0.0004), Bulleidia (p = 0.012), Fusobacterium (p = 0.018), Parvimonas (p = 0.003), Mogibacterium (p = 0.012), Aminobacterium (p = 0.019), Proteus (p = 0.028), Actinomycineae (p = 0.028), Anaerovorax (p = 0.041), Anaerofilum (p = 0.045), Porphyromonas (p = 0.010). Five taxa were increased in appendices in patients with perforated vs. nonperforated appendicitis: Bulleidia (p = 0.004), Fusibacter (p = 0.005), Prevotella (p = 0.021), Porphyromonas (p = 0.030), Dialister (p = 0.035). Three taxa were increased in rectum samples of patients with appendicitis compared to the normal patients: Bulleidia (p = 0.034), Dialister (p = 0.003), and Porphyromonas (p = 0.026).

CONCLUSION

Specific taxa are more abundant in normal appendices compared to the rectum, suggesting that a distinctive appendix microbiota exists. Taxa with altered abundance in diseased and severely diseased (perforated) samples may contribute to appendicitis pathogenesis, and may provide microbial signatures in the rectum useful for guiding both treatment and diagnosis of appendicitis.

Open appendectomy for pediatric ruptured appendicitis: a historical clinical review of the prophylaxis of wound infection and postoperative intra-abdominal abscess

BACKGROUND

We conducted a 3-decade clinical review of prophylaxis for wound infection and postoperative intra-abdominal abscess after open appendectomy for pediatric ruptured appendicitis.

METHODS

We reviewed the charts of patients with ruptured appendicitis who underwent open appendectomy performed by the same pediatric surgeon at the Hospital for Sick Children, Toronto, Canada, between 1969 and 2003, inclusive. We evaluated 3 types of prophylaxis: subcutaneous (SC) antibiotic powder, peritoneal wound drain and intravenous (IV) antibiotics. We divided the sample into 4 treatment groups: peritoneal wound drain alone (group 1); peritoneal wound drain, SC antibiotic powder and IV antibiotics (group 2); SC antibiotic powder and IV antibiotics (group 3); and IV antibiotics alone (group 4). We used the χ(2) test with Bonferroni correction for multiple comparisons.

RESULTS

There were 496 patients: 348 (70%) boys and 148 (30%) girls, with a mean age of 7 (range newborn to 17) years. There were 90 (18%) wound infections. Compared with the current standard of practice, IV antibiotics alone (group 4), peritoneal wound drain (group 1) was associated with the lowest number of wound infections (7 [7%], p = 0.023). There were 43 (9%) postoperative intra-abdominal abscesses. Compared with IV antibiotics alone, SC antibiotic powder with IV antibiotics (group 3) was associated with the lowest number of postoperative intra-abdominal abscesses (14 [6%], p = 0.06).

CONCLUSION

Over a 35-year period of open appendectomy for pediatric ruptured appendicitis, wound infection was least frequent in patients who received prophylactic peritoneal wound drain, and postoperative intra-abdominal abscess was least frequent in those who received prophylactic SC antibiotic powder and IV antibiotics.

Eosinophils, mast cells, nerves and ganglion cells in appendicitis

INTRODUCTION

Twenty to thirty percent appendices removed from patients with suspected appendicitis appear normal on histology. The cause of pain in these patients is unknown. The presence of eosinophils and mast cells should be looked at skeptically which may explain the cause of pain. The aim was to study the eosinophils, mast cells, nerves and ganglions in normal and inflamed appendices.

MATERIALS AND METHODS

A total of 329 appendices including 192 case of acute appendicitis (group A), 94 cases of clinically acute but histologically normal appendices (group B), 13 cases of complementary/elective appendicectomies (group C) and 30 normal controls from medico-legal autopsies(group D), were studied for the presence of eosinophils, mast cells, nerves and ganglia in mucosa, submucosa and muscularis propria. Routine haematoxylin and eosin stained sections were used for eosinophils, nerves and ganglia and Toludine blue sections for mast cell counts. One way ANOVA and logistic regression was used for statistical analysis

RESULTS

The mean eosinophil and mast cell counts were significantly higher in mucosa, submucosa and muscularis propria in Group A and B, when compared to group C+D. The number of nerves and ganglion cells were significantly higher in group A when compared to groups B and C+D. The correlation between eosinophil and mast cell count was not found to be statistically significant.

CONCLUSION

A significant increase in Eosinophils, mast cells, nerves and ganglion cells was seen in acute appendicitis. Increase in eosinophils and mast cells may explain the pain in histologicaly normal but clinically suspected acute appendicitis.

Anti-lipopolysaccharide antibodies in acute appendicitis detected by ELISA

In acute appendicitis the bowel transmissibility of the intestinal flora increases in relation to inflammation and edema formation. We can therefore observe an immunologic response in patients, which is detectable using different bacteria isolated from the normal intestinal flora. Our aim was to measure this immunologic reaction and to detect the relationship between this response and histologic types of acute appendicitis. Sera from 47 cases, comprising 38 patients suffering from appendicitis and 9 healthy controls, were examined. The sera were taken shortly before appendectomy and 14 days after operation. The antigens were lipopolysaccharides (LPS) extracted from bacteria of normal intestinal flora: Escherichia coli O21, O22, O33, O61, O68, Bacteroides fragilis and an absolute rough mutant: Shigella sonnei Re 4350. Antibodies were detected by ELISA. We showed a direct relationship between severity of appendicitis and registered antibody titer. Both aerobic and anaerobic bacteria play a role in infection in appendicitis. According to our serologic results the synergy of B. fragilis with E. coli from normal flora is more important in the initiation of inflammation, but in the perforation process the role of E. coli seems more important compared to that of B. fragilis.

Antibiotics versus placebo for prevention of postoperative infection after appendicectomy

BACKGROUND

Appendicitis is the most common cause of acute abdominal pain requiring surgical intervention. The cause of appendicitis is unclear and the mechanism of pathogenesis continues to be debated. Despite improved asepsis and surgical techniques, postoperative complications, such as wound infection and intraabdominal abscess, still account for a significant morbidity. Several studies implicate that postoperative infections are reduced by administration of antimicrobial regimes.

OBJECTIVES

This review evaluated the use of antibiotics compared to placebo or no treatment in patients undergoing appendectomy. Will these patients benefit from antimicrobial prophylaxis? The outcomes were described according to the nature of the appendix, as either simple appendicitis (including the non-infectious stage) and complicated appendicitis. The efficacy of different antibiotic regimens were not evaluated.

SEARCH STRATEGY

We searched The Cochrane Central Register of Controlled Trials (Cochrane Library 2005 issue 1); Pubmed ; EMBASE; and the Cochrane Colorectal Cancer Group Specialised Register (April 2005). In addition, we manually searched the reference lists of the primary identified trials.

SELECTION CRITERIA

We evaluated Randomised Controlled Trials (RCTs) and Controlled Clinical Trials (CCTs) in which any antibiotic regime were compared to placebo in patients suspected of having appendicitis, and undergoing appendectomy. Both studies on children and adults were reviewed. The outcome measures of the studies were: Wound infection, intra abdominal abscess, length of stay in hospital, and mortality.

DATA COLLECTION AND ANALYSIS

Eligibility and trial quality were assessed, recorded and cross-checked by two reviewers.

MAIN RESULTS

Forty-five studies including 9576 patients were included in this review. The overall result is that the use of antibiotics is superior to placebo for preventing wound infection and intraabdominal abscess, with no apparent difference in the nature of the removed appendix. Studies exclusively on children and studies examining topical application reported results in favour to the above, although the results were not significant.

AUTHORS' CONCLUSIONS

Antibiotic prophylaxis is effective in the prevention of postoperative complications in appendectomised patients, whether the administration is given pre-, peri- or post-operatively, and could be considered for routine in emergency appendectomies.

Antibiotics versus placebo for prevention of postoperative infection after appendicectomy

BACKGROUND

Appendicitis is the most common cause of acute abdominal pain requiring surgical intervention. The cause of appendicitis is unclear and the mechanism of pathogenesis continues to be debated. Despite improved asepsis and surgical techniques, postoperative complications, such as wound infection and intraabdominal abscess, still account for a significant morbidity. Several studies implicate that postoperative infections are reduced by administration of antimicrobial regimes.

OBJECTIVES

The objective of this review is to evaluate the use of antibiotics with placebo or no treatment in patients undergoing appendectomy. Will these patients benefit from antimicrobial prophylaxis? The outcomes are described according to the nature of the appendix, as either simple appendicitis (including the non-infectious stage) and complicated appendicitis. This review do not attempt to compare the effect of different regimens. That clinical question is addressed in another review undertaken by Bleuer 1999.

SEARCH STRATEGY

We searched The Cochrane Controlled Trials Register (Cochrane Library 2002 issue 4); Pubmed, Embase and the Cochrane Colorectal Cancer Group Specialised Register (Up to October 2002). In addition we manually searched the reference lists of the primary identified trials.

SELECTION CRITERIA

We evaluated Randomised Controlled Trials (RCTs) and Controlled Clinical Trials (CCTs) in which any antibiotic regime were compared to placebo in patients suspected of having appendicitis, and undergoing appendectomy. Both studies on children and adults were reviewed. The outcome measures of the studies were: Wound infection, intra abdominal abscess, length of stay in hospital, and mortality.

DATA COLLECTION AND ANALYSIS

Eligibility and trial quality were assessed, recorded and cross-checked by two reviewers.

MAIN RESULTS

Forty-five studies including 9576 patients were included in this review. The overall result is that the use of antibiotics is superior to placebo for preventing wound infection and intraabdominal abscess, with no apparent difference in the nature of the removed appendix. Studies exclusively on children and studies examining topical application reported results in favour to the above although the results were not significant.

REVIEWER'S CONCLUSIONS

Antibiotic prophylaxis is effective in the prevention of postoperative complications in appendectomised patients, whether the administration is given pre-, peri- or post-operatively, and could be considered for routine in emergency appendectomies.

Appendicitis in the elderly

BACKGROUND

Acute appendicitis in the elderly (i.e. those over 60 years of age) is associated with high morbidity and mortality rates. The present retrospective study reviews 10 years ( 1986-1996) of experience and outcome in treating acute appendicitis in patients aged 60 or above.

METHODS

One hundred and thirty patients with acute appendicitis were identified and their case notes reviewed.

RESULTS

Acute appendicitis was diagnosed at admission in 84 patients (64.6%). The remaining patients were observed for a median duration of 9.4 h prior to diagnosis and treatment. Patients with an underlying perforated acute appendix had a significantly longer period of pain prior to admission (P = 0.029; Mann-Whitney U-test) but perforation per se was not associated with a significantly higher rate of morbidity and longer length of hospital stay. In contrast, the use of midline or paramedian incisions was associated with a higher wound infection rate (P=0.003; Pearson chi-squared test) and a longer hospital stay (P<0.001; Mann Whitney U-test). None of the patients were subsequently found to have an underlying colonic neoplasm. The overall morbidity rate was 28%. The mortality rate was 2.3% and all three patients who died had a severe comorbid medical condition prior to developing acute appendicitis.

CONCLUSIONS

Acute appendicitis in the elderly is still associated with significant morbidity. But once acute appendicitis is diagnosed, then expedient surgery, appropriate use of perioperative antibiotics and a right lower quadrant incision can help to minimize the morbidity. Pre-existing severe comorbid medical condition(s) is a major contributory factor to mortality in these patients.

[Antibiotic prophylaxis in colorectal surgery]

In elective colorectal surgery, the benefit of preoperative antibiotic prophylaxis is well established, with a reduction in wound infection rate to less than 10%. The antimicrobial agent used has to be active against aerobic and anaerobic pathogens such as Escheria coli and Bacteriodes fragilis. The efficacy of three schemes of administration: oral and/or parenteral prophylaxis associated with a mechanical preparation, has been demonstrated. Oral antibiotic administration is current practice in USA; the most widely used oral regimen is the combination of erythromycin and neomycin given the day before surgery. Parenteral prophylaxis with a cephalosporin active against Bacteriodes fragilis such as cefoxitin and cefotetan, is preferred in Europe. The issue of whether a systemic prophylaxis should be added to the oral regimen or not has not yet been resolved. However it seems that the association should be proposed in various situations: patients with a high risk factors score (rectal resection and operations lasting more than three hours), patients with incomplete mechanical preparation, delay of the onset of surgery after the last oral dose.

Intra-abdominal sepsis: the role of surgery

The role of the surgeon in intra-abdominal sepsis is multifactorial. A comprehensive understanding of the incidence and pathophysiology of diseases which cause intra-abdominal sepsis is the key to the diagnosis and treatment of such ailments. In simplest terms, the aetiology has two basic mechanisms: (a) violation of the 'bug-body barrier' and (b) obstruction to the flow of a body fluid with subsequent bacterial overgrowth. Either of these mechanisms may affect any of the organs within the abdomen, leading to sepsis. The peritoneal cavity is a dynamic structure which responds to insults in certain predictable manners which notify the alert physician that danger is present. Recognition of these signs through history and physical examination are the most important aspects of diagnosis. Confirmation of suspicions can be obtained with radiological modalities, but they are not a substitute for clinical judgement. Treatment of intra-abdominal sepsis should always begin with resuscitation and systemic antibiotics. Alleviation of the septic source is mandatory, and this may be achieved either operatively or non-operatively (i.e. percutaneous or endoscopic procedures). When the patient does not improve after the initial procedure, then a missed focus of infection must be investigated. In some cases, a planned or staged second operation may be needed to further debride necrotic tissue. Antibiotics should be of adequate spectrum and bioavailability to kill the species of bacteria most likely to cause the infection. This regimen may be altered when culture and sensitivity reports are completed. Finally, patients whose immune system function has been altered by disease or treatment must be assumed very ill until proven otherwise. These are general guidelines in the management of patients with intra-abdominal sepsis. Individual cases may necessitate slight modifications, but all require a high level of vigilance and expertise in order to combat a very lethal disease.

Preventing wound infection after appendicectomy: a review

An exponential increase in the number of published prospective studies reflects both a continuing interest in, and a lack of consensus on, the optimal prophylaxis of wound sepsis after appendicectomy. Review of the literature over the last 25 years leads us to emphasize both the importance of adequate study size and of stratification of the severity of the sepsis found at operation. For critical comparison of prophylactic regimens the high percentage of wound infections disclosed after discharge from hospital must be taken into account. Antibiotics reduce the frequency of wound sepsis and although low wound sepsis rates have been reported with systemic antibiotics active against only anaerobes, the cumulative evidence favours a spectrum of antibacterial activity against both aerobic and anaerobic organisms. Topical antiseptics have no significant effect but topical antibiotics are beneficial. Wide variations in outcome for similar antibiotic regimens reflect the importance of technical factors in determining the frequency of wound sepsis.

Cefotaxime lavage in children undergoing appendicectomy

In an attempt to reduce postoperative sepsis, a series of randomised, double-blind studies was begun in 1982, using cefotaxime as backbone therapy. Up to 1985 (stages I and II), the best results were obtained using a combination of cefotaxime (75 mg/kg intravenously in 3 doses at 12-hourly intervals) plus metronidazole (10 mg/kg intravenously in 3 doses), both drugs administered 1 hour before surgery (preoperatively) or at anaesthetic induction (peroperatively). In 300 consecutive cases, the wound infection rates were 1% in uncomplicated acute appendicitis and 5% in perforated/gangrenous appendices. The present study (stage III) reports the findings in 401 consecutive patients: 215 treated with the above regimen, either pre- or perioperatively (group 1) and 186 who additionally had peritoneal lavage with cefotaxime 2 g/L during surgery (group 2). There were 16 wound infections overall, 2 among patients administered prophylaxis preoperatively and 14 in those administered prophylaxis perioperatively. All produced mixed cultures, with Escherichia coli, Streptococcus milleri and Bacteroides fragilis predominating. The overall figures for postoperative sepsis are 12/215 (5.6%) in the non-lavage group and 8/186 (4.3%) in the lavage group. Among patients with a perforated and/or gangrenous appendix, the wound infection rate was 8/72 (11.1%) in the non-lavage group (group 1) and 4/66 (6.1%) in the lavage group (group 2). Each group had 2 cases of pelvic abscess.

Metronidazole prophylaxis in acute mural appendicitis: failure of a single intra-operative infusion to reduce wound infection

The efficacy of a single 500 mg intravenous intra-operative dose of metronidazole in the prevention of postoperative wound infection, following appendicectomy for acute mural appendicitis, was studied in a prospective randomized placebo controlled trial. Fourteen of the 96 patients (14.6%) in the metronidazole group and 13 of the 94 in the placebo group (13.8%) developed postoperative wound infection. Late sepsis was noted in 4 out of the 96 patients in the metronidazole group and in one of the 94 patients in the placebo group. This study suggests that a single intra-operative dose of metronidazole dose not reduce the incidence of postoperative wound infection following appendicectomy for acute mural appendicitis.

Perioperative prophylaxis with sulbactam and ampicillin compared with metronidazole and cefotaxime in the prevention of wound infection in children undergoing appendectomy

Sulbactam is a beta-lactamase inhibitor, which when administered with ampicillin, increases the latter agents antibacterial activity against beta-lactamase producing organisms. One hundred children between the ages of 5 and 14 undergoing emergency appendectomy were entered into a prospective randomized trial comparing sulbactam and ampicillin (SA) with metronidazole and cefotaxime (MC) as prophylaxis against postoperative wound infection. Patients in whom the appendix was perforated or gangrenous received a 72-hour course of antibiotics, others received a single dose only. The overall wound infection rate was 8% (14% in patients with perforation or gangrene and 4% in those without). There was no difference in infection rate between the two antibiotic groups; there were three wound infections and one subphrenic abscess in patients receiving SA and four wound infections in patients receiving MC. SA, therefore, appears to be a suitable antibiotic combination for use as prophylaxis in appendicitis in children.

Selected overview of nongynecologic surgical intra-abdominal infections. Prophylaxis and therapy

True prophylaxis of intra-abdominal nongynecologic infections is limited to elective, nonemergency surgery and is best shown in three clean-contaminated surgical procedures. All of these have an infection rate of approximately 10 to 20 percent and include all colon resection surgery, most gastric surgery, and about one third of the cholecystectomies for chronic calculous cholecystitis. Each of these three surgical procedures has a somewhat different pattern of bacterial pathogens. The most useful comparative studies of early preoperative therapy have been performed in cases of suspected appendicitis (50 percent of which usually show perforation or gangrene at the time of surgery) and penetrating abdominal wounds (80 percent of which usually enter some part of the bowel and theoretically soil the peritoneum). These procedures are usually classified as contaminated, with a 20 to 30 percent infection rate, or dirty, with a more than 30 percent infection rate, depending upon several factors. Comparative investigations of intraoperative and postoperative antibiotic therapy of established intra-abdominal infections are more difficult to obtain because of the heterogeneity of the sites, organisms, and medical and surgical therapy. The initial pathogens causing secondary peritonitis and hepatic, perirectal, diverticular, and most other types of intraperitoneal abscesses are mixed coliforms and anaerobes, with emphasis on the anaerobes. Retroperitoneal abscesses, pancreatic abscesses, and biliary tract infections are predominantly caused by coliforms. The organisms responsible for these early infections are usually community-acquired rather than more antibiotic-resistant hospital-acquired bacteria. Considering the availability of a large number of effective broad-spectrum antibacterial agents and therapeutic combinations, it has become increasingly difficult to assess the rightful place of any new prospective antimicrobial regimen unless it has quite unique characteristics. Most empiric therapy in established intra-abdominal infection studies have compared gentamicin and clindamycin, the most popular regimen in the United States over the past 15 years, with a cephalosporin, broad-spectrum penicillin, or aminoglycoside, either alone or together with clindamycin or metronidazole. Results have usually been considered similar in most studies, although in some studies, agents with limited Bacteroides fragilis activity, such as cefamandole or cefaperazone, have been considered inferior. Most new prophylactic regimens have been compared with the first-generation cephalosporins and, again, similar results have been obtained between the groups with two exceptions. Cepha

Randomized, prospective, and double-blind trial of new beta-lactams in the treatment of appendicitis

A prospective, randomized, and double-blind study was conducted with 864 patients operated on for appendicitis. In early cases, including normal and acute appendicitis, one dose of antibiotic was given. The rate of postappendectomy septic complications in patients who received cefotaxime, cefoperazone, or moxalactam was very low (about 3%), and there was no statistical difference between the drugs. For late cases, including gangrenous and perforated appendicitis, the antibiotics were continued for 5 days. Moxalactam decreased significantly the septic complications in these patients when compared with the other two drugs. It is safe, free from serious toxic side effects, and more convenient and easier to administer than combination antibiotic therapy. The main disadvantage of moxalactam is its high cost, but this has to be balanced against the savings in nursing time, the cost of monitoring renal function and serum level when aminoglycosides are used, and the reduced usage and manipulation of infusion sets.

[Anaerobic lumen and mucosal microflora of the gastrointestinal tract]

With the model of one-egg twins the importance of the genotype for the development of an individual constant composition of the anaerobic and total microflora of the gut has been shown. Individual characteristics of the mucosal flora have been proved by experimental results of rectum mucosal microflora on normal conditions as well as with appendicitis. In individuals the microflora of the lumen corresponds with that of the mucosa.

Role of obstruction in the pathogenesis of acute appendicitis

The role of obstruction in the pathogenesis of acute appendicitis was studied by measuring the pressure in the appendix perioperatively in 24 patients operated on with an appendectomy because of suspected acute appendicitis. The technique used involved inserting a fine needle through the apex into the appendix lumen and measuring the hydrostatic pressure required to inject saline solution. In three patients with a gangrenous appendix found at operation, and in two patients with a phlegmonous appendix, there were signs of obstruction of the appendix lumen as revealed by increased pressure within it. In 14 patients with a phlegmonous appendix found at operation, no signs of obstruction were found. These experimental data suggest that obstruction is not an important causative agent of acute appendicitis, but might develop as a result of the inflammatory process.

A Danish multicenter study: cefoxitin versus ampicillin + metronidazole in perforated appendicitis

A prospective controlled randomized-block multicenter study was carried out in 209 patients undergoing surgery for perforated or ruptured appendicitis. The patients received either cefoxitin or ampicillin + metronidazole for 5 days. The treatment was started peroperatively. In both groups wound infections were found to be less than 10 per cent and no difference could be demonstrated. However cefoxitin was significantly superior to ampicillin + metronidazole in preventing intra-abdominal abscesses (P less than 0.05). Cefoxitin offers a single drug treatment that adequately reduces postoperative infectious complications in patients undergoing surgery for perforated or ruptured appendicitis.

Prophylaxis of postappendicectomy sepsis by metronidazole and cefotaxime; a randomized, prospective and double blind trial

A randomized, prospective and double blind trial was conducted on 308 patients. Thirty-one out of 102 patients receiving metronidazole developed wound infection compared with 13 out of 103 patients receiving cefotaxime and 14 out of 103 patients receiving metronidazole and cefotaxime. The reduction in the wound sepsis by the use of cefotaxime or a combination of metronidazole and cefotaxime was statistically significant when compared with patients who received metronidazole only. For early cases including normal, acutely inflamed and gangrenous appendices, we gave a single dose of antibiotics just before operation. For late cases with perforation and abscess formation, the antibiotics were continued for 5 days. There was no statistical difference in wound infection between patients who received cefotaxime alone and these who received a combination of metronidazole and cefotaxime.

Metronidazole and ticarcillin in the prevention of sepsis after appendicectomy

Ticarcillin was compared with metronidazole in the prevention of wound infection after appendicectomy. Two hundred nine patients with a diagnosis of acute appendicitis were admitted to a prospective, randomized study and received 500 mg of metronidazole or 5 g of ticarcillin intravenously before operation. Those patients with gangrenous or perforated appendices received two additional doses of the trial drug at 8 hourly intervals. The overall incidence of wound infections in both the metronidazole and the ticarcillin groups was 9 percent. There were no intraabdominal abscesses. Metronidazole abolished anaerobic wound infections. All the early wound infections (between 2 and 4 days after operation) occurred in patients with gangrenous or perforated appendices. We conclude that ticarcillin is as effective as metronidazole in the prevention of wound infection after appendicectomy, but in high-risk patients, (those with gangrenous or perforated appendices) longer courses of antibiotics should be employed.

A double-blind controlled trial of metronidazole suppositories in children undergoing appendicectomy

A total of 133 children, aged 16 months to 15 years (mean 6.7 years), with presumptive acute appendicitis, was included in a double-blind, placebo-controlled trial of the short-term (72 hour) use of metronidazole suppositories as prophylaxis against post-operative infection. There was no significant difference in the incidence or severity of wound infection or post-operative intra-abdominal sepsis between the metronidazole-treated and placebo groups. It is suggested that intra-rectal metronidazole, when used exclusively, is not sufficient for effective prophylaxis for appendicitis in childhood.

Rational use of antibiotics for perforated appendicitis in childhood

Gangrenous and perforated appendicitis was reviewed in 300 pediatric patients. Those with only gangrene generally had a benign course regardless of whether antibiotic therapy was used. However, patients with local perforation or generalized peritonitis had a high incidence of infective complications if they were not treated with antibiotics. Children treated with ampicillin, gentamicin, and clindamycin had markedly fewer wound infections and abscesses and were able to tolerate a diet and go home sooner than those receiving ampicillin and/or gentamicin.

Pathogenicity of enterococci outside of urinary tract and blood stream

It is evident at this time that enterococci by themselves are able to cause infections outside the bloodstream and the urinary tract only rarely and under very special circumstances in which local defense mechanisms are severely compromised (e.g., by plastic devices). In most instances, they have been found in mixed culture and probably act synergistically with other bacteria to cause damage to the host. They could, however, be carried from their habitat into the bloodstream and eventually cause septicemia. Such a danger is probably heightened if supercolonization is fostered through antibiotics that are ineffective against them, e.g., cephalosporins.

Effect of prophylactic antibiotics in acute nonperforated appendicitis: a prospective, randomized, double-blind clinical study

A prospective, randomized, double-blind clinical study was performed to determined the efficacy of short-term (24 hr) perioperative antibiotics in preventing septic complications after emergency appendectomy for nonperforated appendicitis. The patients were stratified into three clinical arms: Group I (placebo, n = 45), Group II (cefamandole, n = 46) and Group III (cefamandole plus carbenicillin, n = 45). The three groups of patients were similar in regard to age, sex, duration of operation and pathologic classification of the appendix. The overall incidence of infection in the study was 5.1%. The infection rates in Groups II (2.2%) and III (0%) were significantly lower than Group I (placebo) (13.3%), (p less than 0.05). No difference was observed between cefamandole alone and cefamandole plus carbenicillin. Average postoperative hospital days per patient for each group was: Group I - 3.8 days; Group II - 2.9 days; Group III - 3.1 days. Cost analysis of hospitalization including cost of prophylactic antibiotics revealed a $247.99 per patient saving for Group II versus Group I and $95.53 for Group III versus Group I. Systemic prophylactic antibiotics can successfully reduce septic complications after appendectomy for nonperforated appendicitis, and a single drug (cefamandole) directed at the facultative pathogens is as effective as double drug therapy, which includes specific anaerobic coverage.

Randomized, prospective trial of topical hydrogen peroxide in appendectomy wound infection. High risk factors

Two hundred seventeen patients were admitted to a randomized and prospective trial of the use of topical hydrogen peroxide prophylactically against wound infection after appendectomy through a gridiron incision. One hundred nine patients received topical hydrogen peroxide and 108 patients were in the control group. There was no statistically significant difference in the wound infection rates in the two groups. Risk factors found to be associated with a significantly higher wound infection rate were (1) age greater than 40 years, (2) duration of symptoms of over 36 hours, (3) generalized guarding, tenderness or rebound, (4) state of the appendix at operation, (5) serous or purulent peritoneal effusion, (6) subjective difficulty of operation as assessed by the surgeons, and (7) positive bacterial culture from the appendicular fossa.

Prophylaxis of infection after appendicectomy: a survey of current surgical practice

Two hundred and eighty questionnaires were sent to junior surgical staff throughout England inquiring about their use of systemic antibiotic prophylaxis, topical antibacterial agents, and surgical drainage in appendicectomy. One hundred and seventy-five (63%) replies were received from 81 of the 87 hospitals included in the survey. Prophylactic systemic antibiotics were used by 78 surgeons (46%) when operating on a normal appendix but by 168 (99%) when the organ had perforated. Most surgeons started antibiotics before operation, but proportionately fewer did so when the appendix was gangrenous or perforated. Patients with severe contamination tended to receive longer courses of antibiotics, although the duration of administration varied considerably. Metronidazole was included in over 95% of all the prophylactic regimens and was often combined with other drugs when the appendix was gangrenous and perforated. Topical antibacterial agents were applied to the wound routinely by only 45 surgeons (26%), although 106 (61%) used them sometimes. Povidone-iodine was the agent most commonly used. Only 98 surgeons (56%) ever drained appendicectomy wounds, while 135 (77%) sometimes drained the peritoneal cavity. Evidence suggests that present methods of giving systemic antibiotic prophylaxis should continue, but that topical agents and surgical drainage are perhaps unnecessary when surgeons are confident of the efficacy of the systemic treatment used.

Single dose intra-rectal metronidazole as prophylaxis against wound infection following emergency appendicectomy

A prospective placebo controlled randomized trial was carried out in 104 patients with a presumptive diagnosis of acute appendicitis. A single dose of 1 g of metronidazole was given intra-rectally 1 h preoperatively. There were 16 wound infections, 15 (out of 50) in the placebo group, 1 (out of 54) in the metronidazole group. This study supports the already accepted value of metronidazole but suggests that a single intra-rectal dose regimen is adequate for prophylaxis.

Prophylactic metronidazole in appendicectomy: a controlled trial

Prophylactic metronidazole was compared with no treatment in a randomly allocated study of patients undergoing appendicectomy. A 1-g suppository of metronidazole was given with the premedication and 200 mg t.d.s. orally for 7 days thereafter. There were 4 hospital wound infections in the 87 patients receiving metronidazole and 11 out of 83 in the no-treatment group (P < 0.05). However, 60 per cent of wound infections occurred at home and the overall infection rates were not significantly different. The duration of postoperative hospital stay was longer in the control group (5.8 days +/- 3.0 s.d.) than in the treated group (4.8 +/- 2.3; P < 0.01). Only one anaerobic infection occurred in a patient receiving metronidazole but late infection was not prevented. Blood levels of metronidazole taken at the end of operation showed a wide variation but there was no correlation with subsequent infection. Culture of the appendix showed aerobic organisms in 88 per cent of cases and anaerobes in 72 per cent. It is suggested that an antibiotic which is effective against both aerobic and anaerobic organisms might have an advantage over metronidazole in appendicitis.

Pre- and postoperative rectal metronidazole for the prevention of wound infection in childhood appendicitis

Children suspected of having appendicitis were treated with preoperative metronidazole per rectum and then postoperative metronidazole per rectum until the drug could be administered orally. This series shows that even when administered after anesthetic induction, an adequate blood level of metronidazole was achieved at surgery. Other antibiotics were not used even when there was peritonitis. The wound infection rate in this small series was low, when compared to other series and our own comparison group.

The importance of anaerobic infections in abdominal surgery

The clinical significance of anaerobic bacteria in infective complications occurring in intestinal surgery is discussed. For high-risk patients the authors recommend parenteral prophylactic administration of clindamycin and gentamicin.

Rational use of antibiotic therapy after appendicectomy

A prospective randomised trial was carried out on 263 patients admitted for appendicectomy. In those patients with normal or inflamed appendix only, wound sepsis occurred in five (5%) of the 96 patients receiving metronidazole compared with seven (7%) of the 91 controls. In patients with gangrenous or perforated appendices, however, 15 of the 32 patients (47%) receiving ampicillin and five (16%) of 31 patients receiving metronidazole developed a wound infection (p less than 0.025). Therapeutic courses of metronidazole significantly reduced wound sepsis rate in those with gangrenous or perforated appendices. Together with another antibiotic it should form part of the management of such patients, but antibiotics are unlikely to reduce further the low rate of wound infection in patients with normal or inflamed appendices.

Wound infection: a controlled clinical and experimental demonstration of synergy between aerobic (Escherichia coli) and anaerobic (Bacteroides fragilis) bacteria

Pathogenic synergy between Escherichia coli and Bacteroides fragilis was suggested by clinical trials and proved to exist in an experimental guinea-pig wound model. This finding is thought to have important theoretical and practical therapeutic implications.

A double-blind trial of a single intravenous dose of metronidazole as prophylaxis against wound infection following appendicectomy

One hundred patients undergoing appendicectomy through a right iliac fossa incision were randomized to receive normal saline or 500 mg metronidazole as an intravenous infusion during the operation. One patient in the saline group developed an erythematous rash. There were 13 wound infections (as defined by the discharge of pus), 12 (out of 51) in the saline group and 1 (out of 49) in the metronidazole group. Bacteroides spp. were frequently cultured from the lumen of removed appendices and from pus obtained from infected wounds. This work supports the value of metronidazole but suggests that a single-dose regimen is adequate for prophylaxis.